Gnathia marleyi is a species of crustacean in the family Gnathiidae. It is named after reggae musician Bob Marley. It is a parasite that infests and feeds on the blood of such fish as the French grunt (Haemulon flavioliniatum). This tiny species is only found in the Caribbean Sea. It only eats while in the juvenile stage. It can be found hiding among sea sponges, algae, and pieces of dead coral.